Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   1      9 inch        baked pie shell
   3                    egg separated
   1      cup           sugar
     1/4  cup           flour all purpose
     3/4  cup           buttermilk
   1      teaspoon      white vinegar
   1      teaspoon      vanilla extract
     1/4  cup           margarine melted
   1                    egg white
                        ground cinnamon

Preparation:

Heat oven to 4250 F. Beat egg yolks until light; gradually add sugar, continuing to beat. Fold in flour and buttermilk alternately. Stir in vinegar, vanilla, and melted margarine. Beat 4 egg whites until fairly stiff peaks form; fold into yolk mixture. Pour into pie shell; sprinkle with cinnamon. Bake for 10 minutes; reduce heat to 3250 F and bake until firm, about 20 minutes. Cool before serving.